<template>
    <div class="pr tl" style="padding: 0 25px 20px 25px;">
      <h1 class="pt30" style="font-size: 23px;font-weight: normal;">填写验证</h1>
      <p class="f12 mt10" style="color: #A5A5A5">请输入下方图片上的数字进行验证</p>
      <canvas canvas-id="s-canvas" @tap="refreshCode"></canvas>
      <view class="f15 mt10 mb10" @tap="refreshCode">看不清楚换一张?</view>
      <view class='info-write flex align-center '>
        <i class='iconfont'>&#xe663;</i>
        <input placeholder="请输入验证码" class="tc" v-model="getIdentifyCode" maxlength="4"/>
      </view>
      <button class="mt10 fp-button" @tap="judgeIdentify">{{text}}</button>
    </div>
</template>

<script type="ECMAScript 6">
  export default {
    name: "image-authentication",
    props: {
      changeSteps: {
        type: Number,
        default: 0
      },
      matters: {
        type: Boolean,
        default: false
      },
      fontSizeMin: { // 字体最小值
        type: Number,
        default: 40
      },
      fontSizeMax: { // 字体最大值
        type: Number,
        default: 50
      },
      backgroundColorMin: { // 验证码图片背景色最小值
        type: Number,
        default: 200
      },
      backgroundColorMax: { // 验证码图片背景色最大值
        type: Number,
        default: 220
      },
      dotColorMin: { // 背景干扰点最小值
        type: Number,
        default: 60
      },
      dotColorMax: { // 背景干扰点最大值
        type: Number,
        default: 120
      },
      contentWidth: { // 容器宽度
        type: Number,
        default: 200
      },
      contentHeight: { // 容器高度
        type: Number,
        default: 50
      }
    },
    watch: {
      matters (newV, olV) {
        if (newV !== null) {
          this.makeCode(this.identifyCodes, 4);
          this.drawPic();
        }
      }
    },
    data () {
      return {
        identifyCodes: '1234567890QWERTYUIOPASDFGHJKLZXCVBNMqazwsxedcrfvtgbyhnujmiklop',
        getIdentifyCode: '',
        identifyCode: '',
        text: '下一步',
      };
    },
    onReady () {
      this.makeCode(this.identifyCodes, 4);
      this.drawPic();
    },
    methods: {
      randomNum (min, max) {
        return Math.floor(Math.random() * (max - min) + min);
      },
      // 生成一个随机的颜色
      randomColor (min, max) {
        let r = this.randomNum(min, max);
        let g = this.randomNum(min, max);
        let b = this.randomNum(min, max);
        return 'rgb(' + r + ',' + g + ',' + b + ')';
      },
      refreshCode () {
        this.makeCode(this.identifyCodes, 4);
        this.drawPic();
      },
      makeCode (paramsCode, l) {
        this.identifyCode = '';
        for (let i = 0; i < l; i++) {
          this.identifyCode += paramsCode[this.randomNum(0, paramsCode.length)];
        }
      },
      // 验证码的判断
      judgeIdentify () {
        this.text = '正在校验验证码···';
        setTimeout(() => {
          if (this.getIdentifyCode === '') {
            wx.showToast({
              title: '未输入验证码！',
              duration: 2000,
              icon: 'none' });
              this.getIdentifyCode = '';
          } else if (this.getIdentifyCode !== this.identifyCode) {
            wx.showToast({
              title: '验证错误！！',
              duration: 2000,
              icon: 'none' });
              this.getIdentifyCode = '';
          } else {
            this.changeSteps ++;
            this.$emit('getChangeSteps', this.changeSteps);
            this.$emit('matters', false);
          }
          this.text = '下一步';
          this.refreshCode();
        }, 2000);
      },
      drawPic () {
        let ctx = wx.createCanvasContext('s-canvas');
        ctx.textBaseline = 'bottom';
        // 绘制背景
        ctx.fillStyle = this.randomColor(this.backgroundColorMin, this.backgroundColorMax);
        ctx.fillRect(0, 0, this.contentWidth, this.contentHeight);
        // 绘制文字
        for (let i = 0; i < this.identifyCode.length; i++) {
          this.drawText(ctx, this.identifyCode[i], i);
        }
        this.drawLine(ctx);
        this.drawDot(ctx);
        ctx.draw();
      },
      drawText (ctx, txt, i) {
        ctx.fillStyle = this.randomColor(50, 160); // 随机生成字体颜色
        ctx.font = this.randomNum(this.fontSizeMin, this.fontSizeMax) + 'px SimHei'; // 随机生成字体大小
        let x = (i + 1) * (this.contentWidth / (this.identifyCode.length + 1));
        let y = this.randomNum(this.fontSizeMax, this.contentHeight - 5);
        var deg = this.randomNum(-30, 30);
        // 修改坐标原点和旋转角度
        ctx.translate(x, y);
        ctx.rotate(deg * Math.PI / 180);
        ctx.fillText(txt, 0, 0);
        // 恢复坐标原点和旋转角度
        ctx.rotate(-deg * Math.PI / 180);
        ctx.translate(-x, -y);
      },
      drawLine (ctx) {
        // 绘制干扰线
        for (let i = 0; i < 4; i++) {
          ctx.strokeStyle = this.randomColor(100, 200);
          ctx.beginPath();
          ctx.moveTo(this.randomNum(0, this.contentWidth), this.randomNum(0, this.contentHeight));
          ctx.lineTo(this.randomNum(0, this.contentWidth), this.randomNum(0, this.contentHeight));
          ctx.stroke();
        }
      },
      drawDot (ctx) {
        // 绘制干扰点
        for (let i = 0; i < 30; i++) {
          ctx.fillStyle = this.randomColor(0, 255);
          ctx.beginPath();
          ctx.arc(this.randomNum(0, this.contentWidth), this.randomNum(0, this.contentHeight), 1, 0, 2 * Math.PI);
          ctx.fill();
        }
      }
    }
  };
</script>

<style lang="stylus" scoped>
  i
    color #22B14A; font-size 20px;
  canvas
    width 200px; height 50px; border-radius: 4px; margin  10px auto;
  .fp-button
    margin 15px  0  0 0; background #22B14A; border-color #22B14A; color #fff; border-radius 4px; text-align center;
</style>
